This invention relates to trench shoring assemblies of the type including a pair of interconnected spaced side walls and, in particular, to a type of trench shoring assembly known as a trench box which includes a stacking accessory to interconnect stacked sets of side walls.
Trench boxes are a type of trench shoring assembly used in excavation work when pipe or conduit is being laid. Basically, a trench box comprises two side walls spaced apart a fixed distance from each other by a plurality of spreader devices which are affixed to and perpendicular to each side wall. The assembled trench box is positioned within an excavated hole or trench and pipe is laid within the trench box, and after each length of pipe is laid the trench box is moved along the trench for laying the next length of pipe. The side walls keep the excavated area free from earth which may fall or cave into the excavated hole or trench before or during the laying of the pipe.
In a deep excavated hole it is desirable to stack two trench boxes, one upon the other, in order to provide the excavation workers greater protection from earth falling from the top of the excavated hole. In the past, the side walls of the two assemblies were secured together by stacking pins located at the four squared off corners of the side walls opposite the bottom triangularly shaped ends of the side walls, the bottom two side walls being driven into the ground. The present invention provides for a simpler yet sturdier way of attaching the two trench box assemblies together. Stacking lugs are welded to the top spreader devices of each of the two trench box assemblies and stacking lug pins interconnect the stacking lugs. In this way the two trench box assemblies are interconnected at the strongest points of each trench box assembly, i.e. the spreader devices.
In accordance with the subject invention there is provided a trench shoring assembly of the type including a pair of interconnected spaced wall means with connecting means interconnecting the spaced wall means and lug means extending from the connecting means for attachment to mating lug means extending from a second connecting means associated with a second pair of spaced wall means for interconnecting stacked sets of spaced wall means. The lug means includes a plurality of flanges extending from the connecting means, the flanges having holes therethrough for receiving locking pins to interconnect the flanges with mating flanges of the mating flange means.